Heat treatable sputter-coated glass systems

ABSTRACT

A heat treatable sputter-coated layer system for glass substrates may be applied before heat treatment if the layer system includes a metallic layer (C) of nickel or a high nickel content alloy covered by separate layers (B,D)  of metallic silicon or an oxide or nitride of nickel or the high nickel content alloy, which in turn is covered by a protective metal oxide such as stoichiometric Sn 02(layers A,E).   &lt;IMAGE&gt;

FIELD OF THE INVENTION

This invention relates to glasses provided with specific coatings whichmay be thereafter heat treated at temperatures sufficiently elevated tobend, heat strengthen, and/or temper the glass. This invention findsparticular utility in architectural and automotive glass production.

BACKGROUND OF THE INVENTION

The popularity of metal and metal oxide coated glasses in architecturaland automotive design is well known. As reported prolifically in patentand other literature, such glasses, through the manipulation of thecoating's layering system, usually by choice of metals and/or metaloxides and/or thicknesses, can usually achieve, quite acceptably, thedegree of reflectance, transmittance, emissivity and durability, as wellas the color desired. See, for example, in this respect, U.S. Pat. Nos.3,935,351; 4,413,877; 4,462,883; 3,826,728; 3,681,042; 3,798,146; and4,594,137 just to name a few.

It has also been well reported that While several reasonably acceptabletechniques exist for applying such coatings, one of the mostefficacious, and thus preferred, is the well known technique referred toas "magnetically enhanced sputter-coating". Such a technique is reportedin U.S. Pat. No. 4,166,018, a recognized fundamental teaching on thesubject. (See also, Munz et al. "Performance and Sputtering Criteria ofModern Architectural Glass Coatings" SPIE Vol. 325 Optical Thin Films,1982 pp. 65-73.)

While efficacious for many known layer systems, the use ofsputter-coating has been known to result in mechanical durabilityqualities less than that achieved by another known method called the"pyrolytic" technique. As a reverse function, however, sputter-coatedsystems often achieve better infrared reflectance than typical pyrolyticcoatings. Also, sputter-coated glasses have generally been recognized ashaving superior optical and thermal performance characteristics thanpyrolytically formed coatings, such as having improved coatinguniformity, good emittance, and better solar performancecharacteristics. It is clear, that if a sputter-coating technique couldbe devised for a particular coating system wherein the mechanicaldurability qualities of the sputter-coated system could approach orequal that of a pyrolytic technique, while at the same time achievingthe enhanced benefits of sputter-coated technology, a significant stepforward in the art would be made. The subject invention described below,in the preferred embodiments thereof, achieves this long-felt need inthe art.

In recent years, the popularity of coated glasses has occasionednumerous attempts at achieving a coated glass article which prior toheat treatment can be coated, and which thereafter, can be heat treatedwithout adversely changing the characteristics of the coated glassarticle. One of the reasons for this is, for example, that it can beextremely difficult to achieve a uniform coating on an already bentpiece of glass. It is well known that if a flat glass surface can becoated and thereafter bent, much simpler techniques can be used to get auniform coating than if the glass has been previously bent.

Certain techniques have been developed in the past for making heattreatable glass articles which may then, and thereafter, be heat treatedby way of tempering, bending, or a technique known as "heatstrengthening". Generally speaking, many of these prior techniques havesuffered from not being truly heat treatable at the higher elevatedtemperatures necessary to achieve economic bending, tempering, and/orheat strengthening (i.e. 1150° F.-1450° F.). In short, such techniqueshave often suffered from a need to keep the temperature at approximately1100° F. or less in order to achieve heat treatability without adverselyaffecting the glass or its substrate.

In this respect, however, two of the inventors of this invention havepreviously invented and offered for sale certain prior art coatingsystems which can be heat treated successfully at the higher, moreelevated temperatures aforesaid, to achieve tempering, bending, or heatstrengthening. Generally speaking, these prior art coating compositionsfind their uniqueness in a layering system which employs as a metalliclayer, a high nickel content alloy which, in its preferred form, is analloy known as Haynes 214, consisting essentially of 75.45% Ni, 4.00%Fe, 16.00% Cr, 0.04% C, 4.50% Al, and 0.01% Y (percentages are byweight). By using a high nickel content alloy, such as Haynes 214, andovercoating it with stoichiometric tin oxide (Sn O₂) either alone orwith other layers (such as an undercoating of the same stoichiometrictin oxide and/or an intermediate layer of aluminum between the top Sn O₂layer and the high content nickel alloy), it was found that heattreatability of glass articles at elevated temperatures of fromapproximately 1150° F.-1450° F. from about 2-30 minutes, could beachieved without substantial degradation of color, durability, chemicalresistance, emissivity, reflectance or transmittance. These compositionstherefore constituted a significant improvement over prior heattreatable systems such as those disclosed in the following U.S. Pat.Nos.: 4,790,922; 4,816,034; 4,826,525; 4,715,879; and 4,857,094.

In addition to the above disclosures in the aforesaid patents, theLeybold "Spectrum" windshield glass system TCC-2000 is also known. Inthis system, four or five layers of metals and metal oxides are employedto obtain a sputter-coated glass which, being somewhat heat treatable attemperatures up to 1100° F. may be used as a pre-coated glass for makingbent or unbent, glass windshields, provided that rapid time limits areplaced on the heat treatment. The layering from glass substrateoutwardly usually includes a first layer of tin oxide, a second layer ofnickel/chrome alloy (usually about 80/20), a third layer of silver, afourth layer of the nickel/chrome alloy, and a fifth layer of tin oxide.In addition to the rather low upper limit on heat treatment temperaturesand times, the resultant coatings are rather soft and exhibit suchunacceptably low chemical resistance characteristics that they canrealistically be used only on the inner surfaces of laminated glasswindshields.

In the aforesaid U.S. Pat. No. 4,715,879 it is specifically taught thatthe layering system therein can not be achieved unless the protectivelayer of a metal oxide (e.g. tin oxide) be formed such that the oxidehas an oxygen deficit (i.e. is non-stoichiometric). This, of course,requires delicate balancing in the manufacturing process. Heattreatability, in this respect, is also disclosed in U.S. Pat. No.4,826,525. However, in this patent it is specifically taught that alayer of aluminum must be applied to achieve heat treatability.

The alloy most preferred for use as the high content nickel alloy (i.e.a nickel alloy having a nickel content greater than about 50% by weight)in the practice of this invention is an alloy produced by HaynesInternational Corporation known as Haynes Alloy No. 214. This alloy is anickel-based, high temperature alloy that is known for its excellentresistance to oxidation, carburization, and chlorination. Its nominalchemical composition is as stated aforesaid. While this particularunique alloy, as well as nickel and/or other alloys thereof having anickel content by weight of greater than about 50% have been found to beuseful in the practice of the subject invention, it is not by the use ofthese alloys alone that the improvements achieved by the subjectinvention are realized. The improvements, instead, are realized from aunique layering system, as opposed to a particular layer in and ofitself.

There are three different types of heat treatments that are generallyemployed in working glass for architectural or automotive purposes;namely, bending, tempering, and a lesser form of tempering called "heatstrengthening" or "hardening". When bending without temperingconventional 1/4" clear float glass, for example, times of 10-30 minutesat 1150° F. or more, are generally necessary to use. In heatstrengthening or tempering such glasses, with or without bending,temperatures as high as about 1450° F. (e.g. 1150° F.-1450° F.) arenormally employed for about 2-5 minutes. As can be seen, there aresignificant drawbacks to many of the known or reported prior arttechniques which are limited in their upper temperatures, for providingheat treatable, coated glasses, particularly of the efficacioussputter-coated type. By the term "heat treatable" as used herein,therefore, is meant that the coated (layered) glass can undergo one ormore of the above three treatments, and that in the preferred forms ofthis invention heat treatability can take place for the requisiteperiods of time at temperatures of from 1150° F.-1450° F.

Coated glasses for use in architectural or automotive design (e.g.vehicular privacy windows) generally have eight (8) characteristicswhich determine their efficacy and/or marketability: commercialfeasibility, durability (mechanical resistance to abrasion), chemicalresistance, long-term stability, emissivity, transmittance,reflectivity, and color. In prior systems, including those developed bytwo of the inventors herein, as reported hereinabove, some of thecharacteristics had to be significantly compromised in order to achievethe necessary degree of acceptability for the remaining characteristics.For example, in the case of the inventors' prior systems, while hightemperature heat treatability was achieved, mechanical durability wasnot optimized. For this and other reasons, therefore, it is apparentthat there exists a need in the art for a heat treatable, coated glassuseful in architectural and/or automotive design which does notsignificantly compromise any of the above eight characteristics, andwhich preferably also may be heat treated (i.e. bent, tempered and/orheat strengthened) at the upper temperature ranges and times of suchtreatments. There is also a need for a coating which can be formed bysputter-coating techniques, but which also achieves the mechanicaldurability of pyrolytically formed coatings.

It is a purpose of this invention to fulfill the above-described needs,as well as other needs apparent to the skilled artisan from thefollowing detailed description of this invention.

SUMMARY OF THE INVENTION

Generally speaking, this invention fulfills the above-described needs inthe art by providing a heat treatable sputter-coated glass articlecomprising a glass substrate having thereon a layer system whichincludes:

(a) a substantially non-oxidized metallic layer formed of nickel or anickel alloy having greater than about 50% by weight nickel;

(b) a metallic oxide protective layer wherein the metal in the metaloxide is different than the metal in layer (a); and

(c) a separate layer of silicon or a metal oxide or nitride layerintermediate layers (a) and (b) wherein the metal in the metal oxide ornitride is nickel or a nickel alloy having greater than about 50% byweight nickel, and wherein layer (c) tightly bonds layer (a) to layer(b).

In certain preferred forms of this invention the aforesaid heattreatable glass article comprises a glass substrate having thereon acoating which includes:

(a) a first layer comprised of an oxide of a metal selected from thegroup consisting of tin, zinc, titanium, and alloys thereof;

(b) a second layer comprised of an oxide or nitride of a metal selectedfrom the group consisting of nickel and a nickel alloy having at leastabout 50% by weight nickel;

(c) a third layer comprised of a metal selected from the groupconsisting of nickel and a nickel alloy having at least about 50% byweight nickel;

(d) a fourth layer comprised of an oxide or nitride of a metal selectedfrom the group consisting of nickel and a nickel alloy having at leastabout 50% by weight nickel; and

(e) a fifth layer comprised of an oxide of a metal selected from thegroup consisting of tin, titanium, and alloys thereof.

In particularly preferred forms of this invention all oxides formed arestoichiometric. For example, in certain preferred forms of thisinvention the above first and fifth layers consist essentially of astoichiometric oxide of tin (Sn O₂), while the second and fourth layersare stoichiometric oxides of the same metal which is employed in themetallic third layer.

Most preferably in this invention, the metal of the second, third andfourth layers constitutes the aforesaid Haynes Alloy No. 214. When thisparticular alloy is employed and the aforesaid layering system is used,the invention is found to have unique applicability in the areas ofvehicular glass, particularly glass known as "privacy windows".

This invention also envisions within its scope a method of forming aheat treatable coated glass article which comprises sputter-coating ontothe glass substrate in the sequence given below from glass outwardly,the following layers:

(a) an optional first layer comprised of an oxide of a metal selectedfrom the group consisting of tin, zinc, titanium and alloys thereof;

(b) an optional second layer comprised of an oxide or nitride of a metalselected from the group consisting of nickel and a nickel alloy havingat least about 50% by weight nickel;

(c) a third layer comprised of a metal selected from the groupconsisting of nickel and a nickel alloy having at least about 50% byweight nickel;

(d) a fourth layer comprised of metallic silicon or an oxide or nitrideof a metal selected from the group consisting of nickel and anon-siliceous nickel alloy having at least about 50% by weight nickel;and

(e) a fifth layer comprised of an oxide of a metal selected from thegroup consisting of tin, zinc, titanium and alloys thereof.

In certain preferred forms of this method, the sputter-coating of eachof said oxide layers is conducted in an atmosphere sufficiently rich inoxygen so as to create substantially stoichiometric oxides. Thepreferred forms of the various layers are as set forth above indescribing the heat treatable glass article envisioned within the scopeof this invention.

Further included within the scope of this invention is a method forforming a coated, heat treated glass article comprising:

(a) forming a substantially non-oxidized metallic layer of nickel or analloy having greater than about 50% by weight nickel;

(b) separately forming on layer (a) a metallic silicon or metal oxidelayer wherein the metal in said oxide is nickel or an alloy havinggreater than about 50% by weight nickel;

(c) separately forming on layer (b) a protective layer of asubstantially stoichiometric metallic oxide; and

(d) thereafter heat treating said article by one of the aforesaidtreatments within the definition of the term "heat treating".

As aforesaid, the preferred layering systems employed are those asdescribed above. In particularly preferred embodiments of this inventionthis method of heat treatment includes carrying out this heat treatmentat temperatures in the range of about 1150° F.-1450° F. for a timesufficient to effect the necessary heat treatment. These particularlypreferred forms, of course, also include applying the coatings by way ofsputter-coating, as aforesaid. It is also envisioned within the scope ofthis invention that various glasses may be employed, the preferred formsof the glass being float glass in untinted or tinted (e.g. green tinted)form.

This invention also envisions within its scope heat treated articlesmanufactured by the aforesaid methods of this invention. Such articlescan take many shapes or forms, but in certain preferred embodimentsconstitute heat treated (tempered, heat strengthened, and/or bent)vehicular privacy windows exhibiting the necessary characteristics forsuch a commercial glass.

This invention will now be described with reference to certainembodiments thereof as illustrated in the following drawings:

IN THE DRAWINGS

FIG. 1 is a partial, sectionalized view of a typical coating system ascontemplated by this invention, applied to a glass substrate which mayin the preferred embodiments be a vehicular privacy window.

FIG. 2 is a schematic of an Airco-Temescal three-zone architecturalsputter-coater useful in carrying out an embodiment of this invention.

FIG. 3 is a schematic of an Airco-Temescal five-zone architecturalsputter-coater useful in carrying out an embodiment of this invention.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIG. 1, there is illustrated in side sectional view atypical example of a glass article coated according to this invention.Therein is illustrated a glass article (substrate) G and a five-layersystem A-E. The layering system and its various combinations will bedescribed hereinbelow. First, however, it should be understood thatglass substrate G may take many forms and be of many types. Preferably,however, in the practice of this invention glass substrate G is typicalfloat glass, either clear or tinted. Green tinting has been found to beparticularly preferred in the practice of this invention when glasssubstrate G is a vehicular privacy glass window (shown here in FIG. 1 inpartial sectional view).

In certain embodiments of this invention coating layers A and B areoptional. Coating layer C is the metallic layer envisioned in thepractice of this invention, which metallic layer consists essentially ofnickel or a high nickel content, non-siliceous alloy (i.e. anon-siliceous nickel alloy having a nickel content of greater than about50% by weight, and most preferably greater than about 70% by weight).

Envisioned within the scope of this invention is not only pure nickel,but nickel alloys such as Inconel, nichrome, and other well known highcontent nickel alloys. Particularly preferred for the purposes of thisinvention, however, is the high content non-siliceous nickel alloy knownas Haynes No. 214. Such an alloy has a nominal composition as describedhereinabove.

Layer D is a particularly important layer for the purposes of thepractice of this invention in that it serves not only as a tight bondingmechanism between layers C and E but it is also believed to addsignificantly to the heat treatable characteristics of the preferredembodiments of this invention. Layer D, in this respect, is a separatelayer formed by sputter-coating and may consist essentially of eitherelemental silicon (Si) or an oxide (preferably stoichiometric) of ametal selected from nickel (Ni), or an alloy (preferably non-siliceous)having greater than about 50% by weight nickel. In particularlypreferred embodiments of this invention layer D is a separately formedoxide layer whose metal is the same metal as has been employed informing layer C.

Layer E is a protective layer which is a metal oxide (preferablystoichiometric) of a metal selected from the group consisting of zinc,titanium, tin, and alloys thereof. However, in the preferred forms ofthis invention this protective layer E consists essentially ofstoichiometric tin oxide (Sn O₂).

The above three layers constitute the essential layers found in thepractice of this invention. However, certain optional layers may beadded, and in the preferred embodiments of this invention, they havebeen found to add significant improving characteristics to certainproducts as envisioned within the scope of this invention. In thisrespect, layer A is yet another protective layer which also serves tobond layer B to the glass substrate. Thus layer A should have thecharacteristic of not only protecting the layered system fromundesirable effects from the glass substrate G, but also will serve as atight bonding agent between substrate G and layer B. In the preferredembodiments of this invention layer A may be selected from the samegroup of oxides as is layer E, and in particularly preferred embodimentsit is the same metallic oxide employed as layer E, and in this respect,is most preferably stoichiometric tin oxide (Sn O₂).

Optional layer B serves the same function as layer D except that it nowtightly bonds layer C to layer A. Layer B may be selected from the samemetal oxides as are employed in making layer D, and in this respect, inits preferred embodiments, constitutes an oxide of the same metalemployed as the metal in layer C. In the most preferred forms, ofcourse, the metal of layers B, C, and D is Haynes 214, while that oflayers A and E is tin.

The technique for coating employed in this invention may be any of theknown coating methods, but in particularly preferred forms it is theaforementioned sputter-coating techniques which, in carrying out theinvention, may be practiced by the use of any conventionalsputter-coater, such as a conventional Airco-Temescal multi-zonearchitectural sputter-coater of known design. As shown in FIG. 2, thissputter-coater may take its conventional form wherein there are employedthree targets in each of three zones, thus resulting in targets 1-9.Glass substrate G, herein shown as a flat glass sheet (e.g. in the shapeof a flat, yet to be bent and/or tempered vehicular privacy window) isconveyed on conveyor 11 (roller type only schematically shown) throughthe Airco sputter-coater whose zones are separated in a known fashion bywalls F having in their lower extremity an adjustable tunnel T. Pre-wash13 and post-wash 15 are conventionally provided.

Because of these tunnels T in walls F, oxide coatings can be formed atthe interface with proper regulation of pressures or selective additionof oxygen at nozzles O₂, while the substantially non-oxidized metalliclayer can be formed in the middle of Zone 2. Thus, for example, withreference to applying the coating of FIG. 1 as the coating on substrateG as it progresses through the three-zone apparatus shown in FIG. 2, allthree targets 1-3 may be of the same protective metal (e.g. tin). Inthis situation, the pressure in Zone 1 may be regulated to approximately2-3×10⁻³ Torr with an 80% O₂ and 20% argon atmosphere. Zone 2 may thenhave as its targets the various elements desired for layers B, C, and D,while Zone 3 will have the metal desired for layer E. By applying apressure in Zone 2 less than in Zone 1, and using 100% argon as theatmosphere (and/or selectively using oxidizing nozzles O₂), andthereafter applying a pressure of 1.0×10⁻³ -3×10⁻³ Torr in Zone 3, fivelayers may be formed as shown in FIG. 1 in the following manner:

As glass G progresses through Zone 1 at its aforesaid pressure,stoichiometric tin oxide is applied to the glass as layer A if thisoptional layer is desired. By creating a higher pressure in Zone 1 thanZone 2, oxygen flows into Zone 2 and/or the first nozzle O₂ is opened,such that if target 4 is to be employed to create optional layer B, thecoating therefrom will be oxidized (preferably stoichiometrically).Target 4, in this respect, can be formed of nickel, Inconel, nichrome,Haynes 214, or other high content nickel alloys.

Insufficient oxygen is allowed to reach the area under target 5 so thatessentially pure metal is now formed as a layer C on top of separatelyformed layer B. Thus target 5 can be the same as target 4, or within thesame class as described. If, now, layer D is desired to be silicon, thentarget 6 is made of silicon and Zone 3 may be controlled at a pressurelower than that in Zone 2 (e.g. 1×10⁻³ Torr) and second nozzle O₂ isclosed, such that essentially unoxidized silicon is formed as layer D.If, on the other hand, it is now desired to form layer D of the sameoxide as layer B, then the pressure in Zone 3 is made to exceed that inZone 2 (e.g. 3×10⁻³ Torr) and/or second nozzle O₂ is opened, so that anoxide (preferably stoichiometric) is created as layer D. Here, when notsilicon, target 6 is conveniently of the same material or class ofmaterial as target 4 (and preferably the same as target 5 as well).

As glass G then progresses into Zone 3, targets 7, 8 and 9 provide theprotective metal oxide coating (e.g. stoichiometric Sn O₂, the same aslayer A). This, then, completes the heat treatable coating system.Engaging from the end of Zone 3 is a tightly adhering, excellent coatingsystem having outstanding levels of the eight characteristics includingmechanical durability as listed above. It is to be pointed out, in thisrespect, that in the circumstances of this invention, whether usingclear float glass or the preferred green tinted float glass, layer C, inwhatever form employed, does not change the index of refraction of theglass substrate either before or during the heat treatment.

It is apparent from the drawing in FIG. 2 that other permutations andcombinations of the targets may be employed. For example, rather thanrelying upon pressure 25 differentials between the zones, and/or the useof nozzles O₂, it may be desirable to use targets 3 and/or 7 for apurpose other than to help create the protective layer. In oneembodiment then, targets 1-2 and 8-9 may be Sn, while targets 3-7 areHaynes 214. By using substantially equal pressures in the zones (and/ornot employing either target 4 or target 6) a five-layer system asenvisioned by this invention is formed, because the Haynes 214 oxide isnow created in the same zone where the Sn O₂ layers are formed. Inanother embodiment, of course, target 6 could be Si and target 7 couldbe inoperable, thus creating another layer system within the scope ofthis invention. Various other combinations will be apparent to theskilled artisan once given this disclosure.

FIG. 3 illustrates an alternative procedure for creating theabove-described layering system. In this embodiment a conventionalfive-zone Airco-Temescal sputter-coater is employed. Nine targets, 1-9,of fifteen targets may be used (or all 15 targets can be used). In thisembodiment, furthermore, targets 1-3 and 7-9 are preferably of the metalto be employed as the protective oxide (e.g. preferably stoichiometrictin oxide, Sn O₂) and, of course, the various permutations andcombinations as suggested above may be substituted here, because 15targets are available.

The difference, then, between this embodiment and that of FIG. 2 is thatby employing a separate zone for each individual layer, differentialpressures and/or the use of special oxidizing nozzles O₂ need not beemployed. All that is normally needed, in this respect, is the controlof the appropriate atmosphere in a known fashion to achieve the desiredresult in any given zone. For example, a nominal pressure of about2×10⁻³ Torr may be employed in all five zones and thereafter, byemploying either a 100% argon atmosphere, or an atmosphere of 80% O₂ and20% argon, either an essentially metallic layer (100% argon) or astoichiometric oxide coating (80% O₂, 20% Ar) may be formed. In thisrespect, of course, it is understood that, if desired, differentialpressures and/or nozzles O₂ (not shown) may be selectively used as theywere described with respect to the embodiment of FIG. 2, to achieve aparticular result. It is also understood, with regard to bothembodiments, that the number of targets employed may be varied toachieve a particular result such as thickness, speed, etc. All of thisis well known to the skilled artisan familiar with the technique ofsputter-coating.

While thicknesses can be varied to achieve the desired end result, inaccordance with simple trial and error techniques, it is preferred forthe purposes of this invention to maintain the layers within thefollowing general ranges:

    ______________________________________                                        Layer         Thickness (Angstroms)                                           ______________________________________                                        A             about 0-1000 (>1 when used)                                     B             about 0-100 (>5 when used)                                      C             about 20-250                                                    D             about 5-100                                                     E             about 20-1000                                                   ______________________________________                                    

While the actual mechanism by which the subject inventive concept andits unique layering systems achieves the high degree of heattreatability and, at the same time, mechanical durability, is not fullyunderstood, nevertheless it is believed that the following condition ndpurposes apply in the normal situation:

    ______________________________________                                        Purposes of Layers                                                            ______________________________________                                        Layer E:  a)    Reduces oxidation of metallic layer C                                         during heat treatment                                                   b)    Increases abrasion resistance of layer                                        stack                                                                   c)    Increases chemical resistance of layer                                        stack                                                                   d)    Adjust optical characteristics of layer                                       stack                                                         Layer D:  a)    Promotes adhesion between layer E and                                         layer C                                                                 b)    Slightly adjusts optical characteristics                                      of layer stack                                                          c)    Increases chemical resistance of layer                                        system                                                        Layer C:  a)    Reflects infrared radiation                                             b)    Reflects visible light                                                  c)    Reduces solar energy transmission                                       d)    Reduces visible light transmission                                      e)    Resists high temperature oxidation                                            during heat treatment                                         Layer B:  a)    Promotes adhesion between layer C                                             and layer A                                                             b)    Slight adjustments to optical                                                 characteristics of layer stack                                          c)    Increases chemical resistance of layer                                        system                                                        Layer A:  a)    Reduces visible light reflectance on                                          glass side (anti-reflective)                                            b)    Reduces interaction between layer C                                           and glass substrate at high temperatures                                c)    Reduces sensitivity of layer C to                                             light stain on surface of glass (glass                                        corrosion by moisture)                                                  d)    Increases chemical resistance of layer                                        system                                                                  e)    Adjust color                                                  ______________________________________                                    

EXAMPLE 1

(FIG. 2, Targets 1-3, 7-9 are Sn; Targets 4-6 are Haynes 214 alloy.Glass: Green Tinted Float Glass)

    ______________________________________                                        Typical Process Conditions:                                                                          (Preferred)                                            ______________________________________                                        Layer E:                                                                      Working Gases - argon and oxygen                                                                     (80% O.sub.2, 20% Ar)                                  Gas Pressure - 0.5 to 5.0 × 10.sup.-3 Torr                                                     (1.0 × 10.sup.-3 Torr)                           Target Voltage - 200-800 volts                                                                       (393 volts)                                            Target Amperage - varies                                                                             (7.4 amps)                                             Target Power - varies  (2.9 kw)                                               Layer D:                                                                      Working Gases - argon and oxygen                                                                     (50% O.sub.2, 50% Ar)                                  Gas Pressure - 0.5 to 5.0 × 10.sup.-3 Torr                                                     (8.9 × 10.sup.-4 Torr)                           Target Voltage - 200-800 volts                                                                       (347 volts)                                            Target Amperage - varies                                                                             (7.4 amps)                                             Target Power - varies  (2.6 kw)                                               Layer C:                                                                      Working Gases - argon and oxygen                                                                     (14% O.sub.2, 86% Ar)                                  Gas pressure - 0.5 to 5.0 × 10.sup.-3 Torr                                                     (7.7 × 10.sup.-4 Torr)                           Target Voltage - 200-800 volts                                                                       (407 volts)                                            Target Amperage - varies                                                                             (7.9 amps)                                             Target Power - varies  (3.2 kw)                                               Layer B: (Same as Layer D)                                                    Layer A: (Same as Layer E)                                                    ______________________________________                                    

Typical Optical Electrical Properties

(Properties Reported on 5/32" (4.0 mm) Green Tinted Float Glass) [Afterfiring in tempering furnace ]

    ______________________________________                                        Visible Transmission:                                                                            22-23% Ill. C, 2° observer                          Visible Reflectance (glass side):                                                                11-12% Ill. C, 2° observer                          Visible Reflectance (film side):                                                                 31-33% Ill. C, 2° observer                          Visible Color (glass side):                                                                      Gray a = 0.5, b = 0.8                                      Visible Color (film side):                                                                       Gold a = 1.0, b = 24.0                                     Emissivity:        0.37-0.38                                                  Sheet Resistance:  35-37 OHMS per square                                      Solar Transmission:                                                                              13-14%                                                     Solar Reflectance: 10%                                                        ______________________________________                                    

EXAMPLE 2

(FIG. 2, Targets 1-3, 8-9 are Sn; Targets 4-7 are Haynes 214 alloy, butTarget 7 is not operable. Glass was 5/32" tinted float glass.)

    __________________________________________________________________________    Typical Process Conditions:                                                                                  Atmosphere                                     Zone                                                                             Target                                                                            Kw Volts                                                                             Amps                                                                              Mat'l.                                                                            Pressure (O.sub.2 %/Ar %)                               __________________________________________________________________________    1  1   20 421 45  Sn  2 × 10.sup.-3 (Torr)                                                             80/20                                          1  2   19 428 45  Sn  "        "                                              1  3   19 427 45  Sn  "        "                                              2  4    2 348 10  214 "        100% Ar                                                                       (background O.sub.2)                           2  5   17 515 31.5                                                                              214 "        100% Ar                                        2  6    5 371 10  214 "        100% Ar                                                                       (background O.sub.2)                           3  7   -- --  --  214 "        80/20                                          3  8   14 390 21  Sn  "        "                                              3  9   12 399 34  Sn  "        "                                              __________________________________________________________________________

In this example nozzles O₂ are employed at the fourth and sixth target(e.g. sccm about 149) to insure oxidation of the Haynes 214 alloy atthese locations. The tinted glass employed was a conventional greentinted float glass having a transition temperature for tempering,hardening and/or bending purposes of approximately 1140° F. -1160° F.Washer speed was set at 70.0% and gas bleed/background in the threezones were (sccm) 1099/275, 480/149, and 893/222, respectively. In Zone2 background tubes (i.e. nozzles O₂) were operable only for targets 4and 6. To insure substantially no oxidation of the Hayes 214 at target5, the voltage was maintained at greater than 505 volts. The resultingcoating was a five-layered system from glass outwardly consistingessentially of: Sn O₂ / 214 oxide/214 metallic/214 oxide/Sn O₂. Alloxides were believed to consist essentially of stoichiometric oxide.

This glass structure in the form of an unbent vehicular privacy windowboardered by a typical boarder paint (e.g. Degussa paint) was thensubjected to a conventional tempering and bending operation (i.e. slumpand press) at oven temperatures of about 1240° F.-1330° F. for timessufficient to achieve the final product. The result was an excellentprivacy window appearing neutral gray from the glass side and gold fromthe coating side, with excellent durability characteristics.

EXAMPLE 3

A privacy window similar to that of Example 2 was created using theprocedures set forth in Example 2, except that target 6 was renderedinoperative and target 7 was employed. An excellent, durable vehicularprivacy window was

As can be seen from the above, the unique systems and methods of thisinvention achieve excellent mechanical durability, optical, and heattreatable characteristics. Once given the above disclosure, therefore,various other modifications, features or improvements will becomeapparent to the skilled artisan. Such other features, modifications andimprovements are thus considered a part of this invention, the scope ofwhich is to be determined by the following claims:

We claim:
 1. A heat treatable glass article comprised of a glasssubstrate having thereon a coating which includes:a) a first layerhaving a thickness of abut 5-100Å and comprised of an oxide or nitrideof a metal selected from the group consisting of nickel and a nickelalloy having at least about 50% by weight nickel; b) a second layerhaving a thickness of abut 20-250Å and comprised of a metal selectedfrom the group consisting of nickel and a nickel alloy having at leastabout 50% by weight nickel; c) a third layer having a thickness of about5-100Å and comprised of an oxide or nitride of a metal selected from thegroup consisting of nickel and a nickel alloy having at least about 50%by weight nickel; and d) a fourth layer having a thickness of about20-1000Å and comprised of an oxide of a metal selected from the groupconsisting of tin, zinc, titanium and alloys thereof.
 2. A heattreatable glass article comprised of a glass substrate having thereon acoating which includes:a) a first layer having a thickness of about1-1000Å and comprised of an oxide of a metal selected from the groupconsisting of tin, zinc, titanium and alloys thereof. b) a second layerhaving a thickness of about 5-100Å and comprised of an oxide or nitrideof a metal selected from the group consisting of nickel and a nickelalloy having at least about 50% by weight nickel; c) a second layerhaving a thickness of abut 20-250Å and comprised of a metal selectedfrom the group consisting of nickel and a nickel alloy having at leastabout 50% by weight nickel; d) a fourth layer having a thickness ofabout 5-100Å and comprised of an oxide or nitride of a metal selectedfrom the group consisting of nickel and a nickel alloy having at leastabout 50% by weight nickel; and A fifth layer having a thickness ofabout 20-1000Å and comprised of an oxide of a metal selected from thegroup consisting of tin, titanium and alloys thereof.
 3. A heattreatable glass article according to claim 2 wherein said first andfifth layers consist essentially of tin oxide.
 4. A heat treatable lassarticle according to claim 2 wherein the metal of said second, third andfourth layers is the same metal.
 5. A heat treatable glass articleaccording to claim 4 wherein the first and fifth layers consistessentially of stoichiometric tin oxide.
 6. A heat treatable glassarticle according to claim 5 wherein said metal of said second, third,and fourth layers consists essentially of an alloy having greater thanabout 70% Ni by weight.
 7. A heat treatable glass article according toclaim 2 wherein said first and fifth layers consist essentially ofstoichiometric tin oxide, said third layer consists essentially of analloy comprised of Ni, Fe, Cr, C, Al and Y, and said second and fourthlayers consist essentially of an oxide of said alloy of the third layer.8. A heat treatable glass article according to claim 6 wherein saidalloy of said third layer consists essentially of:

    ______________________________________                                        ELEMENT              Wt %                                                     ______________________________________                                        Ni                   about 75.45                                              Fe                   about 4.00                                               Cr                   about 16.00                                              C                    about .04                                                Al                   about 4.50                                               Y                    about 0.01                                               ______________________________________                                    


9. A heat treatable glass article according to claim 2 wherein saidglass substrate is green tinted float glass.
 10. A heat treatablesputter-coated glass article comprising a glass substrate having thereona layer system which includes:a) a substantially-oxidized metallic layer(a) formed of nickel or a nickel alloy having greater than about 50% byweight nickel and having a thickness of about 20-250Å; b) a metallicoxide protective layer (b) wherein the metal in the metallic oxide isdifferent than the metal in layer (a) and having a thickness of about20-1000Å; and c) a separate layer (c) intermediate layers (a) and (b)consisting essentially of metallic silicon or a metallic oxide ornitride wherein the metal in the metal oxide or nitride is nickel or anickel alloy having greater than about 50% by weight nickel, and whereinlayer (c) tightly bonds layer (a) to layer (b) and has a thickness ofabout 5-100Å.
 11. A heat treatable sputter-coated glass articleaccording to claim 10 wherein the metal in the oxide of said layer (c)is the same metal as in layer (a).
 12. A heat treatable sputter-coatedglass article according to claim 11 wherein said layer (b) consistsessentially of stoichiometric tin oxide (Sn O₂).
 13. A heat treatablesputter-coated glass article according to claim 12 which furtherincludes layers (d) and (e), wherein layer (c) is a metallic oxide ornitride of nickel or a nickel alloy having greater than about 50% byweight nickel, and wherein layer (e) has a thickness of about 1-1000Åand is the same metallic oxide as layer (b), and layer (d) has athickness of about 5-100Å and is the same metallic oxide or nitride aslayer (c), and wherein layer (e) bonds layer (d) tightly to said glasssubstrate, and layer (d) bonds layer (e) tightly to layer (a).
 14. Aheat treatable sputter-coated glass article according to claim 13wherein said article is a vehicular privacy window.